二维纵向正交复合驱动夹心式压电管形换能器的研究

In order to improve the vibrational performance of the longitudinal and radial vibrational ultrasonic transducers, a novel two-dimensional longitudinal orthogonal composite driving sandwich piezoelectric tubular transducer is proposed. It is composed of a conical pre-stressed elastic expansion bolt, a two-dimensional longitudinal orthogonal composite driving sandwich piezoelectric actuator and a metal tube. So as to get the physical mechanism that how the radial vibration of the metal tube can be excited efficiently by the longitudinal vibration of the two-dimensional longitudinal orthogonal composite sandwich piezoelectric actuator, the following studies are carried out. Firstly, the analytical design theory of the transducer is studied, and its equivalent circuit and resonance frequency equation are deduced. Based on the resonance frequency equation, the relationship between the vibrational characteristic parameters and the geometrical dimensions, the material property are analyzed. Secondly, numerical method is used to simulate the vibrational modes, the resonance frequencies, the pre-stress, the radiation acoustic field of the transducer, and the interdependencies between the vibrational displacement distribution, the radiation acoustic field and the geometrical dimensions, the vibrational modes, the pre-stress of the transducer are obtained. Finally, two optimization methods are proposed to optimize the structure shape and dimension of the transducer. Based on the optimum design results, some two-dimensional longitudinal orthogonal composite driving sandwich piezoelectric tubular transducer are manufactured, in which their vibrational characteristic parameters are measured and compared with the analytical and numerical results. Thus, this research has important significance in providing the theoretical and experimental data for the novel transducer to be successfully applied in the ultrasonic engineering.

为提高现有纵向及径向振动超声换能器的振动性能，本项目提出一种新型二维纵向正交复合驱动夹心式压电管形换能器。该换能器由锥形弹性膨胀预应力螺栓、二维纵向正交复合夹心式压电激励器和金属圆管三部分组成。项目重点研究如何利用二维正交复合夹心式压电激励器的正交纵向振动高效激发管形振子径向振动的物理机制。首先，探讨此类换能器的解析设计理论，推导其正交纵向耦合振动及纵径复合振动的等效电路及共振频率方程；在此基础上探讨换能器的性能参数与其结构尺寸及材料性能的依赖关系。其次，用数值模拟法对换能器振动模态、频率响应、预应力响应、辐射声场等进行仿真，给出换能器的位移分布和辐射声场与其结构尺寸、振动模态及预应力之间的关系。最后，基于理论分析结果，提出两种优化设计方案编程实现换能器的优化设计；利用优化结果加工制作各类工作频率的换能器样品，从实验上验证理论分析结果，为该类换能器的工程应用提供理论设计指导及实验数据。

为提高现有纵向及径向振动超声换能器的振动性能，本项目提出一种新型二维正交复合驱动压电管形换能器。基于解析理论、数值模拟和实验相结合的方法，深入研究了换能器的振动性能，为该类超声换能器在工程中的应用建立了较完整的理论及实验模型。主要研究工作包括：.（1）基于耦合振动理论和机电类比原理，建立了二维正交复合驱动压电管形换能器的各组成部分的机电等效电路及共振频率方程，获得了该换能器的性能参数与其几何结构尺寸及振动模态的依赖关系。.（2）利用数值方法对换能器的振动性能、机电阻抗特性和声辐射特性进行仿真，给出了振动系统的纵向、径向振动位移分布、机电阻抗特性与其振动模式之间的依赖关系，获得了振动系统的最佳几何结构尺寸参数，为该类超声换能器的工程设计提供了参考数据。.（3）依据理论分析结果，设计制作了相应的大功率超声换能器，利用阻抗分析仪、激光测振仪对振动系统的振动性能进行了分析测试，获得了与理论分析相一致的结果。项目研究成果有望在超声液体处理领域获得广泛应用。